The present application finds particular application in vehicle monitoring systems, particularly involving collision avoidance. However, it will be appreciated that the described techniques may also find application in other object monitoring systems, other vehicle systems, or the like.
Conventional methods for determining distance to an object employ a smoothed value for a dimension, which is then later used for ranging. Typical approaches to smoothing may employ a Kalman filter (i.e., a recursive averaging procedure) and therefore suffer from sensitivity to noise. Kalman filtering assumes a certain behavior (e.g. Gaussian noise) for the measurement errors, and can thereby produce erroneous results when the errors are not Gaussian or when a large error occurs. A smooth, continuous, value can be produced using conventional techniques, but this approach masks the underlying discrete and possibly significantly incorrect result.
Traditional object tracking systems use, for example, a vehicle template to track a target vehicle, and then determine a change in size and location of pixels that encompass the target vehicle relative to the vehicle template. In this manner, the change in distance and position of the target vehicle is monitored. Using such approaches, only individual pixel changes are monitored and vehicle size must be continuously recalculated. Other approaches employ radar and camera object detection systems, wherein the radar is used to compute the following distance to a target vehicle, and once the vehicle is no longer within radar range, the camera is used to calculate the following distance by comparing the last known image stored in memory when distance was calculated by the radar and comparing it to a new camera image. For instance, pixel width is compared to vehicle size to determine if the target vehicle is getting further away or closer to the host vehicle. However, such systems must continuously recalculate vehicle size.
The present innovation provides new and improved systems and methods that facilitate performing initial size calculation for a vehicle and monitoring vehicle distance as a function of the initially calculated vehicle size, which overcome the above-referenced problems and others.